Internal combustion engine with hydrogen direct injection

Abstract

The present invention relates to an internal combustion engine with hydrogen direct injection. The engine derives from a traditional diesel cycle engine but is modified and optimized to be powered by hydrogen. Some main characteristics of the injection, ignition and combustion systems of direct fuel injection engines are modified. In particular: the piston and specifically the combustion chamber, the “lay-out” of the injector and the lay-out of the spark plug. The invention is applicable to various types of engines with different bores, cylinder head arrangement, rotation speeds and type of mission. The components can be customized accordingly, while maintaining the commonalities with the corresponding components of traditional diesel engines.

1 . An internal combustion engine with hydrogen direct injection equipped with:
 a cylinder head ( 100 ) equipped with at least one injector ( 20 ) configured to inject a spray ( 21 ) of hydrogen,   at least one piston ( 10 ) the engine being characterized by the fact that:   a combustion chamber ( 40 ) of the piston ( 10 ) has a non-symmetrical geometry with a first portion ( 41 ′), proximal to the injector ( 20 ) less deep than a second portion ( 41 ″), distal to the injector ( 20 ), the non-symmetrical geometry having the function of capturing most of the hydrogen spray ( 21 ) and avoiding direct impact of the hydrogen spray ( 21 ) on the walls ( 42 ′,  42 ″) of the combustion chamber ( 40 ), as well as favoring the best mixing towards the center ( 43 ) of the combustion chamber ( 40 ), and   a connection channel ( 23 ) between the injector ( 20 ) and the combustion chamber ( 40 ) is provided with a converging section ( 22 ) configured to reduce an opening angle (Y′) of the hydrogen spray ( 21 ).   
     
     
         2 . The engine according to  claim 1 , wherein the projection(s) of the spark plug ( 30 ) from a horizontal surface ( 101 ) of the cylinder head ( 100 ), which defines the top of the combustion chamber ( 40 ), is comprised between 0 mm and 2 mm. 
     
     
         3 . The engine according to  claim 1 , wherein:
 the distance (a) along a central axis (X) of the combustion chamber ( 40 ) between a first end ( 40 ′) of the combustion chamber ( 40 ), proximal to the injector ( 20 ), and the center ( 43 ) is greater than the distance (b) along the central axis (X) of the combustion chamber ( 40 ) between a second end ( 40 ″) of the combustion chamber ( 40 ), distal to the injector ( 20 ), and the center ( 43 ); and   the first portion ( 41 ′) of the combustion chamber ( 40 ) has a bottom wall ( 42 ′) whose radius (R 1 ) is greater than the radius (R 2 ) of the bottom wall ( 42 ″) of the second portion ( 41  “).   
     
     
         4 . The engine according to  claim 3 , in which the central axis (X) of the combustion chamber ( 40 ) is rotated around the axis of the piston ( 10 ) as a function of the swirl ratio (SR), by an angle (α) whose values are between 15° and 45°. 
     
     
         5 . The engine according to  claim 1 , in which an angle of inclination (β) of the injector ( 20 ), with respect to a horizontal surface ( 101 ) of the cylinder head ( 100 ), is not less than 20°. 
     
     
         6 . The engine according to  claim 5 , in which the angle of inclination (β) of the injector ( 20 ) is between 40° and 60°, in the case of direct injection at low pressure. 
     
     
         7 . The engine according to  claim 1 , in which the connecting channel ( 23 ) is provided with a first cylindrical section ( 23 ′), proximal to the nozzle ( 24 ) of the injector ( 20 ), and with a second cylindrical section ( 23 ”), distal to the nozzle ( 24 ) and in communication with the combustion chamber ( 40 ), separated by the converging section ( 22 ). 
     
     
         8 . The engine according to  claim 7 , in which the first cylindrical section ( 23 ′) has a length between 20 mm and 40 mm and a diameter almost equal to the diameter of the nozzle ( 24 ). 
     
     
         9 . The engine according to  claim 7 , wherein the second cylindrical section ( 23 ″) has a length comprised between 5 mm and 15 mm and a diameter comprised between 5 mm and 8 mm. 
     
     
         10 . Engine according to  claim 1 , wherein the cylinder head ( 100 ) is provided with a first groove ( 102 ) and a second groove ( 103 ) configured to deflect the hydrogen spray ( 21 ).